Casio fx-3650p and HP
21S: Minimum Loss Matching
This
program takes the incoming impedances Z0 (from left) and Z1 (from right), and
determines the resistance R1 and R2, with the corresponding minimum loss. The program assumes that Z0 and Z1 are both
positive and Z0 ≥ Z1.
Formulas
Used:
R1
= Z0 * √(1 – Z1/Z0)
R2
= Z1 / √(1 – Z1/Z0)
Minimum
loss = 20 * log (√(Z1/Z0) + √(Z1/Z0 -1))
Casio fx-3650P
Input: X = Z0, Y = Z1
Program
(49 steps):
? →
X : ? → Y : Y ÷ X → M :
X √
( 1 – M → A ◢
Y √
( 1 – M → B ◢
20 log
( √ M ^-1 + √ ( M ^-1 – 1 → C
HP 21S
Input: Z0 gets stored in register 0, Z1 gets stored
in register 1
Program
(44 steps):
|
Step
|
Code
|
Key
|
Notes
|
|
01
|
61, 41, C
|
LBL C
|
Start
the program
|
|
02
|
22, 1
|
RCL 1
|
Z1
|
|
03
|
45
|
÷
|
|
|
04
|
22, 0
|
RCL 0
|
Z0
|
|
05
|
74
|
=
|
|
|
06
|
21, 4
|
STO 4
|
|
|
07
|
33
|
(
|
|
|
08
|
1
|
1
|
|
|
09
|
65
|
-
|
|
|
10
|
22, 4
|
RCL 4
|
|
|
11
|
34
|
)
|
|
|
12
|
11
|
√
|
|
|
13
|
21, 5
|
STO 5
|
|
|
14
|
55
|
*
|
|
|
15
|
22, 0
|
RCL 0
|
|
|
16
|
74
|
=
|
|
|
17
|
21, 2
|
STO 2
|
|
|
18
|
26
|
R/S
|
Display
R1
|
|
19
|
22, 1
|
RCL 1
|
|
|
20
|
45
|
÷
|
|
|
21
|
22, 5
|
RCL 5
|
|
|
22
|
74
|
=
|
|
|
23
|
21, 3
|
RCL 3
|
|
|
24
|
26
|
R/S
|
Display
R2
|
|
25
|
33
|
(
|
|
|
26
|
22, 4
|
RCL 4
|
|
|
27
|
15
|
1/x
|
|
|
28
|
11
|
√
|
|
|
29
|
75
|
+
|
|
|
30
|
33
|
(
|
|
|
31
|
22, 4
|
RCL 4
|
|
|
32
|
15
|
1/x
|
|
|
33
|
65
|
-
|
|
|
34
|
1
|
1
|
|
|
35
|
34
|
)
|
|
|
36
|
11
|
√
|
|
|
37
|
34
|
)
|
|
|
38
|
51, 13
|
LOG
|
|
|
39
|
55
|
*
|
|
|
40
|
2
|
2
|
|
|
41
|
0
|
0
|
|
|
42
|
74
|
=
|
|
|
43
|
21, 5
|
STO 5
|
Display
minimum loss (Z)
|
|
44
|
61, 26
|
RTN
|
|
Example:
Input: Z0 = 50, Z1 = 45
Results:
R1 = 15.8113883008, R2 = 142.302494708, Min Loss = 2.84419586692
Source: Casio Scientific Formula 128
fx-1000F/fx-5000F owner’s manual, 1987
Eddie
This
blog is property of Edward Shore, 2017
